The influence of polluted bottom sediments on the quality of water in the Grand Calumet River/Indiana Harbor Canal (GCR/IHC) was investigated. The approach used consisted of obtaining and analyzing existing information on sediment-water interactions and their relationship to water quality, methods for estimating impacts of sediment-water interactions on water quality, and sediment and water quality data for the GCR/IHC system. To understand the role of sediment as a source of contaminants in the GCR/IHC, it is necessary to understand the relative importance of sediment and water from the GCR/IHC as contaminant source to Lake Michigan. Data available on sources of pollutants of the GCR/IHC were examined, and a waste load allocation model developed for the GCR/IHC was evaluated. Study results show that the available data allows only rough estimates, of sediment loadings and sediment yield. However, historical data suggest that dredging the IHC would allow it to act as a sediment trap, retaining contaminated sediment that would otherwise be transported into Lake Michigan. More detailed hydrodynamic and suspended sediment transport data are necessary to allow use of more sophisticated analytical techniques for evaluating sediment sources and for quantifying resuspension and sediment transport in the system. Additional data must also be collected before sophisticated analytical techniques can be applied to the GCR/IHC system for either metals or toxic organics.